Enter your Carrier serial number to find the manufacture date. Works for all Carrier AC units, heat pumps, and furnaces.
Air ConditionerHeat PumpFurnaceAir Handler
Enter Serial Number
How to decode the serial number
Carrier uses a letter-based date code system embedded in the serial number. The position and meaning of the date code changed several times over the decades, so the format depends on the era of manufacture.
2004 to Present (Most Common)
The first two digits are the week of manufacture, the next two are the year.
4406A12345
Position
Meaning
Example
1–2
Week — Week 44 of the year
44
3–4
Year — 2006
06
5+
Sequence — Production sequence (ignore)
A12345
1990–2003
The first letter encodes the week, the second encodes additional info, digits 3–4 are the year.
XA96A12345
Position
Meaning
Example
1
Week code — Letter A=1, B=2... X=week 24 (skipping I, O, Q, U)
X
3–4
Year — 1996
96
Use the week letter table below for this era.
Week Letter Code (1990–2003)
Letters I, O, Q, and U are skipped.
A=Week 1, B=Week 2, C=Week 3... continuing through the alphabet skipping I, O, Q, U.
ABCDEFGHJKLMNPRSTUVWXY
Where to find the serial number
Locate the data plate on your Carrier unit — typically on the side panel of an outdoor AC/heat pump, or inside the furnace cabinet door.
The data plate is usually a silver or white sticker with model number, serial number, voltage, and refrigerant type.
The serial number (S/N) is different from the model number (M/N) — you want the serial number.
For most units manufactured after 2004, the first 4 digits of the serial number give you the week and year.
Decoded examples
2417A12345
→ Week 24, 2017
24 = week 24, 17 = 2017
0812B67890
→ Week 8, 2012
08 = week 8, 12 = 2012
5209C11111
→ Week 52, 2009
52 = week 52, 09 = 2009
Life expectancy
Expected lifespan: 15–20 years for Carrier central AC and heat pumps. 20–25 years for furnaces with proper maintenance.
Common questions
On the outdoor condenser unit, look for the data plate on the side panel — usually near the refrigerant service ports. It's a silver or white sticker listing the model number, serial number, and electrical specifications.
Week 15 of 2006, meaning the unit was manufactured in April 2006. That makes it approximately 18–19 years old as of 2025.
Yes. Carrier uses the same WWYY date code format for furnaces, air handlers, and heat pumps made after 2004. For the furnace, look for the data plate inside the cabinet door.
Units made between 1990–2003 use a letter-based week code. The first letter corresponds to the week of manufacture (A=1, B=2, etc., skipping I, O, Q, U). Digits 3–4 are the 2-digit year.
Most HVAC professionals recommend replacement when a unit is 15+ years old and needs a major repair. The "5,000 rule" — multiply the age by the repair cost, and if it exceeds $5,000, replacement often makes more sense.